Adult criminal offenders in Western Australian are eight times more likely than non-offenders to use community-based mental health services in the year before their first sentence, a UWA study has found.

Published in the journal of Criminal Behaviour and Mental Health, the study is the first to investigate the use of mental health services by various offenders’ sub-groups.

The scientists used administrative mental health service data to compare offenders commencing their first ever criminal sentence in WA from 1985 to 1994, and a matched community group of 21,977 non-offenders.

First author and UWA PhD candidate Nita Sodhi-Berry says the study found the most common diagnosis was substance use disorder.

This diagnosis was about one-and-a-half times more prevalent among Indigenous than non-Indigenous offenders, regardless of gender, she says.

“Offenders in all gender-race groups were more likely to have used these services than similar non-offenders,” Ms Sodhi-Berry says.

“But the effect was strongest for non-Indigenous women, who were over 12 times more likely to have used such services, and weakest among Indigenous men, who were about twice as likely to have used them as their non-offending peers.”

For non-Indigenous offenders, the prevalence of any mental health service contact was higher for violent rather than non-violent offenders, irrespective of gender.

Ms Sodhi-Berry says further research may help understand this differential use of services, especially since Indigenous populations are over-represented in prison.

“This information is important to inform adequate resourcing and provision of community and correctional mental health service infrastructure for this marginalised population,” she says.

Ms Sodhi-Berry says that few studies have yet to investigate the mental health of offenders on non-custodial sentences.

“Although our study could not determine the true prevalence of mental disorders among offenders, we found that offenders on community correction orders were as likely to have used mental health services as prisoners before being sentenced,” she says.

“This finding has important implications for the planning and provision of screening and management procedures for mental disorders in this large group of non-custodial offenders who do not receive the same level of dedicated mental healthcare as is provided to prisoners.”